JP3196993B2 - Thermal fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device used for an image forming apparatus such as a laser beam printer, a copying machine, a facsimile machine and the like.

[0002]

2. Description of the Related Art Generally, as a method of fixing a toner image on a sheet by heating and pressing a sheet having an unfixed toner image adhered to the surface, the sheet is formed of hollow cylindrical aluminum. A heating roller having a halogen lamp fixed to a fixing frame inside, a pressure roller provided with a layer for improving the releasability on the surface of a hard rubber or the like is nipped at a constant pressure, and between the two rollers. There is known an apparatus which allows a sheet on which an unfixed toner image is adhered to pass through. In such a heat fixing device, heat is stored on the surface of the heating roller by supplying power to the halogen lamp, and when the unfixed toner side of the sheet is transported as the heating roller side, the toner is melted by the heat of the heating roller, The image formed by the toner is fixed on the sheet by the pressing force of the pressure roller.

In order to supply power to the halogen lamp of the heating roller in the heat fixing device, a tungsten terminal forming both ends of the halogen lamp is usually connected to a power supply board provided in a printer or the like through a power supply lead wire. Connected to the power supply terminal from

In fixing the halogen lamp to the fixing device frame, a tungsten terminal is pressed against the fixing device frame by a pressing member, and the pressing member is fastened to the fixing device frame by a screw.

[0005]

However, when assembling the heat fixing apparatus, a step of fixing the halogen lamp and a step of connecting the power supply lead wire to the tungsten terminal and the power supply terminal are required. And the number of man-hours for assembling increased, resulting in poor assembling efficiency.

Further, in this heat fixing device, when the halogen lamp is fixed to the fixing device frame, the tungsten terminal is directly pressed against the fixing device frame. When the tungsten terminal is pressed, the tungsten terminal is deformed or damaged. There was a problem that it was not possible to secure energization.

The present invention has been made to solve these problems, and has as its object to provide a heat fixing device which has a small number of parts, is easy to assemble, and can operate stably. Things.

[0008]

According to a first aspect of the present invention, there is provided a heat fixing device comprising: a heating roller including a cylindrical member and a heater inserted therein; A pressure roller is provided opposite to the heating roller and is pressed against the heating roller with a constant pressure, and is supported by a recording medium sent between the heating roller and the pressure roller. the unfixed toner image, a thermal fixing apparatus for heat fixing by energizing the heater, and the rod terminal portion thereof formed heater integrally at both ends of the heater, the rod-like terminal section a pair of terminal holding member having a U-shaped portion which is bent in a U-shape for grasping, a pair of the of the rod-like terminal portion of the both end portions of the heater was arranged to grip at the U-shaped portion the terminal holding member, the terminal holding It at a position away from the U-shaped portion of the timber
By fixing the respective frames, in which the rod-like terminal portion provided with a pair of fixing members to be gripped by the U-shaped portion of the terminal holding member.

The invention described in claim 2 is the first invention.
A thermal fixing apparatus according to one more of the fixing member
With the sticking operation to one of said frames of said terminal holding member by persons, one of the terminal holding member is intended to be secured to the feeding terminal is led from the power supply unit.

[0010] Further, the invention according to claim 3 is based on claim 1.
Or a thermal fixing device according to 2, said fixing member
With the fixing operation to the other of said frame of said terminal holding member by the other, the other of the terminal holding member is secured to one end of the temperature fuse for interrupting the power supply to the abnormal heating of the heater, the temperature The fuse has its periphery covered by a rib formed on the frame.

[0011]

In the thermal fixing device according to the first aspect of the present invention, the heating roller comprises a cylindrical member and a heater inserted therein. The pressure roller is provided opposite to the heating roller, and is pressed against the heating roller with a constant pressure. Then, the unfixed toner image supported on the recording medium fed between the heating roller and the pressure roller, which is heated and fixed by energizing the heater, further the both ends of the heater The terminal holding member, which is disposed so that the integrally formed rod-shaped terminal portion is gripped by the U-shaped portion, is positioned away from the U-shaped portion.
When the fixing member is fixed to the frame at the position , the rod-shaped terminal portion is gripped by the U-shaped portion of the terminal holding member.

Further, in the heat fixing device according to the present invention,
Further, one of the fixing members may be used for the terminal holding member .
With the sticking operation to one of the frame, one of the terminal holding member is fixed to power supply terminals derived from the power supply unit.

According to a third aspect of the present invention, there is provided a heat fixing device comprising:
Furthermore, the other of the fixing members can be used to
With the fixing operation to the other of the frame, the other terminal holding member is also fixed to one end of the temperature fuse for interrupting the power supply to the abnormal heating of the heater, the temperature fuse is formed in the frame The circumference is covered by ribs.

[0014]

Next, an embodiment of the present invention will be described. FIG. 1 is a schematic side sectional view of a printer 1 as an image forming apparatus, and FIG. 2 is a side sectional view of a main part of a developing device. In the printer 1 according to the present embodiment, a paper feed cassette 3 is detachably mounted on one upper side of a main body case 2, and recording media stacked in the paper feed cassette 3 by a paper feed roller 4 and a separation pad 5. Paper is separated one by one and the transport roller pair 6
Is transferred to a photoreceptor unit 9 including a photoreceptor drum 7 and a transfer roller 8. A developing device 1 to be described later is disposed adjacent to the photoreceptor unit 9 and on the side close to the paper feed cassette 3.
The fixing unit 13 including the heating roller 11 and the pressing roller 12 is disposed on the opposite side.
Further, on the downstream side of the fixing unit 13, a paper discharge roller pair 24 for discharging the paper on which the fixing is completed, and a paper discharge tray 25 for stacking the discharged paper are provided.

Below the photoreceptor unit 9, a scanner unit 17 including a laser emitting unit 14, a lens 15, a reflecting mirror 16, etc., control boards 18 and 19, and a power supply unit 20
The cover body 21 is provided with a plurality of operation buttons 22.

A printing operation performed by the printer 1 having such a configuration will be described. First, the surface of the photosensitive drum 7 charged in advance by the charger 23 is irradiated with a laser beam emitted from the scanner unit 17 in accordance with image data transmitted from an external device such as a computer (not shown). An electrostatic latent image is formed on the surface of the photosensitive drum 7.
Next, the latent image was developed into a visible image with the powdery toner supplied and magnetized by the developing device 10, and then supplied between the photosensitive drum 7 and the transfer roller 8. The toner image is transferred to paper. Then, after the fixing unit 13 applies heat and pressure to the transferred image to fix the toner image on the sheet, the sheet is ejected from the sheet ejection roller pair 24 to the ejection tray 25 of the printer 1. is there.

Next, the fixing unit 13 of this embodiment will be described in detail with reference to FIGS.

As shown in FIG. 2, a heating roller 11 made of a cylindrical aluminum or the like constituting the fixing unit 13 has a halogen lamp 31 as a heat source therein.
The halogen lamp 31 has round rod-shaped tungsten terminals 32a and 32b for supplying power to the halogen lamp 31 at both ends. As shown in FIGS. 3 and 4, a temperature for interrupting the power supply to the halogen lamp 31 during abnormal heating is provided at the bottom of the resin fixing device frame 33 for supporting the heating roller 11 from below. A fuse 34 is provided to face the heating roller 11. One end of the thermal fuse 34 is connected to a thermal fuse plate 35 made of a conductive copper plate or the like.
Is connected to one terminal 32b of the halogen lamp 31 by a method described later. Further, the other end of the thermal fuse 34 is grounded through a ground terminal 36.

Since the fixing device frame 33 is provided with a rib 37 that covers the thermal fuse 34 and opens upward, the heat generated from the heating roller 11 is directed toward the thermal fuse 34. It becomes easy to gather, and it operates correctly even in the case of excessive heating due to malfunction of the control device and shuts off the power supply, so that the safe operation of the printer 1 can be guaranteed. Further, when the halogen lamp 31 is abnormally heated, the heating roller 11
Even when the fixing device frame 33 supporting the end of the heating roller 11 is melted down, the heating roller 11 is supported by the rib 37 below, so that the thermal fuse 34 is reliably protected.

As shown in FIG. 3, one end of the fixing device frame 33 is bent into a substantially L-shape for supplying power to the halogen lamp 31 and has a hanging portion 38a and a horizontal portion 38b. Power supply terminal 38 is provided. The hanging portion 38a of the power supply terminal 38 is connected to the control board 18 by a lead wire (not shown). Further, a screw hole 39 for fixing to the fixing device frame 33 is formed in the horizontal portion 38b of the power supply terminal 38 as shown in FIG.

The terminal 32 of the halogen lamp 31
5A, the terminal holding member 41 is formed in a U-shape as shown in FIG. 5 and provided with a screw hole 40 communicating with the overlapping portion, and the U-shaped portion holds the terminal portion 32. The screw holes 39 of the power supply terminals 38 described above are held so as to overlap the screw holes 40 of the terminal holding members 41 and fastened to the fixing device frame 33 with the screws 43 as the fixing members of the present invention. One end of the halogen lamp 31 is fixed to the fixing device frame 33. That is, as shown in FIG.
As described above, the screw hole 40 is a U-shaped portion that holds the terminal portion 32.
From the screw hole 40 (terminal
(At a position away from the U-shaped portion of the holding member 41)
Fix the terminal holding member 41 to the fixing period frame 33.
As a result, the terminal portion 32 of the halogen lamp 31 is
It is gripped by the U-shaped part of the holding member 41.

Further, the terminal portion 32 of the halogen lamp 31
b, a terminal holding member 41 having a similar shape is disposed, and the fixing device frame 3 is connected to the fixing device frame 3 via the temperature fuse plate 35 described above.
3, the halogen lamp 31 is fastened to the fixing device frame 33 by fastening with a screw 43 as a fixing member of the present invention.
Can be completely retained.

As described above, by configuring the fixing unit 13 of this embodiment, the terminal holding member 41 for fixing the halogen lamp 31 inserted into the heating roller 11 to the fixing device frame 33 is fixed. At the same time, since the terminal holding member 41 and the power supply terminal 38 or the temperature fuse plate 35 are connected to supply power to the halogen lamp 31,
Thus, the number of members required for fixing the lamp and supplying power to the halogen lamp 31 can be minimized, and the effect of contributing to a reduction in the number of assembling steps is very large.

Further, since the terminal holding member 41 is gripped so as to protect the terminal portions 32a and 32b of the halogen lamp 31, it is possible to prevent the conventional terminal portions 32a and 32b from being damaged. .

The present invention is not limited to the embodiment having the above-described configuration, and the terminal holding member 41 and the power supply terminal 38 or the terminal holding member 41 and the temperature fuse plate 35 may be integrally formed. It is possible.

[0026]

As described above, according to the present invention, the thermal fixing apparatus of the invention of claim 1, wherein the rod-like terminal portion formed integrally at both ends of the heater disposed so as to grip at the U-shaped portion When the terminal holding member is fixed to the frame at a position away from the U-shaped portion , the rod-shaped terminal portion is gripped by the U-shaped portion of the terminal holding member. In a protected form, preventing damage to the rod-shaped terminal portion and ensuring stable operation.

Further, in the heat fixing device according to the present invention,
In addition to the effect of the thermal fixing device according to claim 1, with the fixing operation to the one frame of the terminal holding member according to one of the fixing member, the power supply terminal to which one of the terminal holding member is guided from the power supply unit Are also connected, so that the number of parts is reduced, thereby significantly reducing the number of steps required for assembling the heat fixing device and facilitating assembly.

Further, in the heat fixing device according to the third aspect of the present invention,
In addition to the effect of the thermal fixing apparatus according to claim 1 or 2, with the fixation operation of the other frame of the terminal holding member by the other of the fixing member, when the other of the heater abnormal heat of the terminal holding member Since it is also connected to one end of the thermal fuse for cutting off the power supply, the number of components is further reduced, and the assembly of the thermal fixing device is further facilitated. Also,
Since the thermal fuse is surrounded by the ribs formed on the frame, the heat generated from the heating roller is more likely to collect in the direction of the thermal fuse. The power supply can be cut off by operating, and even if the frame supporting the end of the heating roller melts down due to abnormal heating of the heater, the heating roller is supported by the ribs, so the thermal fuse can be reliably installed. Protected.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a laser printer.

FIG. 2 is a top view of a heating roller.

FIG. 3 is a front sectional view showing a state in which a heating roller is attached to a fixing device frame.

FIG. 4 is a partial top view of the fixing device frame.

FIG. 5 is a side view showing a state where the halogen lamp is attached to the fixing device frame.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printer 11 Heating roller 31 Halogen lamp 32a, 32b Terminal part 33 Fixer frame 34 Thermal fuse 38 Power supply terminal 40 Screw hole 41 Terminal holding member 43 Screw

Claims (3)

(57) [Claims] 1. A heating roller comprising a cylindrical member and a heater inserted therein, a pressure roller provided opposite to the heating roller and pressed against the heating roller at a constant pressure. A heat fixing device for heating and fixing an unfixed toner image supported on a recording medium sent between the heating roller and the pressure roller by energizing the heater. , and the rod terminal portion thereof formed heater integrally at both ends of the heater were bent in a U-shape to grip the bar-like terminal portion U
A pair of terminal holding member having a shaped portion, a pair of the terminal holding member with the rod-like terminal portions arranged to grip at the U-shaped portion at both ends of the heater, the end
A pair of fixing members for holding the rod-shaped terminal portion by the U-shaped portion of the terminal holding member by being fixed to the frame at a position away from the U-shaped portion of the child holding member. A heat fixing device. 2. Along with the sticking operation to one of said frames of said terminal holding member according to one of the fixing member, wherein one of the terminal holding member is to be fixed also to the power supply terminal derived from the power supply unit The heat fixing device according to claim 1. 3. With the fixing operation to the other of said frame of said terminal holding member by the other of the fixing member, the temperature fuse for the other of the terminal holding member to cut off the power supply to the abnormal heating of the heater Is also fixed to one end of
3. The thermal fixing device according to claim 1, wherein the thermal fuse is covered at its periphery by a rib formed on the frame.